It's quite a past-time. Cheap fun for the family. Can get aggravating though, doing a highly rated cache. I haven't done a 5-5 yet though. You should read up on some of the different varieties. There are spinoffs of the hobby (sport??)
Highly recommended for outdoorsy type folks. Or those who need to get outdoors! I think there are over 1.6 million caches worldwide, and 5 million cachers. Join the fun!
There are some really prolific cachers. TeamSnook....MrsCaptainPicard. Over 13-14,000 finds if I remember right. Must be retired is all I an say.